#include <bits/stdc++.h>

#include <atcoder/modint>
using namespace std;
using mint = atcoder::modint998244353;
void fast_io() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
}

void solve() {
    int n, m;
    cin >> n >> m;
    vector<vector<mint>> dp(m, vector<mint>(3));
    long long c1 = max((long long)n * (n - 3) / 2, 0LL);
    long long c2 = max(c1 - n + 3, 0LL);
    long long c3 = max(c1 - 2 * n + 7, 0LL);
    dp[0][0] = 1;
    dp[0][1] = n;
    dp[0][2] = c1;

    for (int i = 1; i < m; i++) {
        dp[i][0] = dp[i - 1][0] + dp[i - 1][1] + dp[i - 1][2];
        dp[i][1] =
            n * dp[i - 1][0] + (n - 1) * dp[i - 1][1] + (n - 2) * dp[i - 1][2];
        dp[i][2] = c1 * dp[i - 1][0] + c2 * dp[i - 1][1] + c3 * dp[i - 1][2];
    }
    mint ans = dp[m - 1][0] + dp[m - 1][1] + dp[m - 1][2];
    cout << ans.val() << "\n";
}
int main() {
    fast_io();
    int t;
    cin >> t;
    for (; t--;) {
        solve();
    }
}